Conventionally, in such a component mounting apparatus equipped with a component mounting head having a suction nozzle, the component mounting head is moved relative to a component to be mounted onto the board so that the suction nozzle is located above the component. Thereafter, the suction nozzle is lowered so that the component is brought into contact with a sucking-and-holding surface of the suction nozzle, and moreover the component is sucked up by the sucking-and-holding surface so that sucking and holding of the component by the suction nozzle can be achieved. Furthermore, the component mounting head, which is equipped with the suction nozzle having the component sucked and held as described above, is moved to a position above the board, and thereafter the suction nozzle is lowered so that the component is located at the component mounting position on the board, and the suction of the suction nozzle is then stopped to release the suction. Thus, the component can be mounted onto the board.
In recent years, electronic equipment containing electronic circuits formed by the mounting of components on a board has been advanced increasingly toward higher functions, more diversifications or smaller sizes. Together with such advancement for higher functions, more diversifications or smaller sizes in electronic equipment, the component and the board themselves also have been advanced toward higher functions, more diversifications or smaller sizes. Also, various conditions required in the mounting of components onto the board are becoming more diversified and wider in variety, while those conditions themselves are becoming more strict.
Such conditions required for the component mounting as described above are, for example, that diversified and variously shaped components can be sucked and held reliably by the sucking-and-holding surface of the suction nozzle, preventing damage to a component that has become more vulnerable to external loads as a result of the higher functionality, or the like. The external loads mentioned above are exemplified by electrical loads such as static electricity or the like, influences of contamination caused by the degree of cleanliness of ambient environments or others, and the like. In some cases, it is required, as another condition, that the suction nozzle or the component mounting head has durability so as to be ready for repeated component mounting operations.
For use as the suction nozzle to be fitted to the component mounting head, various kinds of suction nozzles have been developed so as to meet the various conditions as described above.
Such various kinds of suction nozzles in the prior art include, for example, a suction nozzle formed from a ceramic material (see, e.g., Japanese unexamined patent publication No. 2000-151200 A). Such a suction nozzle, by virtue of being formed by using ceramics, has an advantage that its durability and wear resistance for repeated use of the suction nozzle can be enhanced.
Another kind of suction nozzle of the prior art is exemplified by a suction nozzle formed with the aim of having the capability of sucking and holding components of various configurations, particularly, of large-size components (see, e.g., Japanese unexamined patent publication No. 2002-233983 A). A schematic sectional view of such a suction nozzle 114 is shown in FIG. 13.
As shown in FIG. 13, the suction nozzle 114 is provided so as to be movable up and down and located inside a hollow-shaft like head body 112 which is fitted to a hollow shaft 111 forming part of the component mounting head. Also, the suction nozzle 114 is equipped with a projecting pin 128 which is held on a through hole 117 within the suction nozzle 114 so as to be movable up and down and biased downward. Further, the suction nozzle 114 has a pad member 122 provided at a downward end of its nozzle body 114a. This pad member 122, having a skirt portion 171 which protrudes in a funnel-like state downward on the outer circumferential side, is made from a soft elastic material.
Further, in the suction nozzle 114, a suction face for sucking a component is formed at its downward end face. On this suction face, a sucking-and-holding portion 125 formed of a rigid body in a generally annular shape integrally with the nozzle body 114a so as to protrude downward around a suction port 181 which opens at the end face of the nozzle body 114a. In addition, the skirt portion 171 of the pad member 122 is formed in such placement as to protrude in a funnel shape slightly downward of the sucking-and-holding portion 125. Also, about 15 μm diamond particles are electrodeposited on a surface of the sucking-and-holding portion 125. It is noted that the suction nozzle 114 is formed from a metal material in consideration of its mechanical strength, simplicity of manufacturing process and the like. The suction face in suction and holding of the component has its skirt portion 171 stretched on the surface of the component while the sucking-and-holding portion 125 is kept in contact with the surface of the component.
Next, in the component mounting head having the construction described above, operations in performing suction and holding of the component by the suction nozzle 114 are described with reference to FIGS. 14A, 14B and 14C.
As shown in FIG. 14A, in the component mounting head, in its normal state, the suction face of the pad member 122 keeps a normal state that it is out of contact with the component, i.e. a state that the skirt portion 171 is projected by its own elasticity slightly downward of the sucking-and-holding portion 125. Also, the projecting pin 128 keeps a state that it is projected by biasing force from the suction port 181 to a specified length, and the suction nozzle 114 is kept at a lower-limit position. In this state, as shown in FIG. 14B, the component mounting head lowers toward the surface of the component 109 within the component feed device 104. Then, when the suction face is pressed against the surface of the component 109, the skirt portion 171 is pushed and expanded outward after the inclination of the component 109 even if the component 109 is inclined, so that the sealability between the suction face and the surface of the component 109 can be enhanced. In this state, operating a vacuum generator causes the component 109 to be held on the sucking-and-holding portion 125 by its suction force.
The component mounting head that has sucked the component 109 as described above, after being located on a specified mounting position of the board 103 as shown in FIG. 14C, moves down to mount the component 109 onto the board 103.
With use of the component mounting head having the suction nozzle 114 as described above, it becomes implementable to reliably suck and hold a large-size component, thus enabling component mounting of such large-size components.